Inertia and Momentum Question

1. The problem statement, all variables and given/known data
Figure 11-45 shows a rigid structure consisting of a circular hoop of radius R and mass m, and a square made of four thin bars, each of length R and mass m. The rigid structure rotates at a constant speed about a vertical axis, with a period of rotation of 2.8 s. Assuming R = 0.62 m and m = 1.2 kg, calculate (a) the structure's rotational inertia about the axis of rotation and (b) its angular momentum about that axis.

2. Relevant equations
I already solved part (a) but the equations to use for part (b) are L=Iw

3. The attempt at a solution
I put in the I that I recieved from part (a) which is 1.5, however I don't know how to find angular velocity... Can anyone help me out?